In automotive electronics, an Electronic Control Unit (ECU) is any embedded system that controls one or more of the electrical systems or subsystems in a transport vehicle. Types of ECU include Electronic/engine Control Module (ECM), Powertrain Control Module (PCM), Transmission Control Module (TCM), Brake Control Module (BCM or EBCM), Central Control Module (CCM), Central Timing Module (CTM), General Electronic Module (GEM), Body Control Module (BCM), Suspension Control Module (SCM), control unit, or control module. In the beginning, each sensor had its own input at the ECU. As the number of sensors increases, the number of inputs at the ECU has to increase too. To decrease the number of sensor inputs at the ECU, sensors are developed which send values of multiple sensors over a serial link. The TLE4998C3 manufactured by Infineon is a programmable Linear Hall Sensor which transmits digitally, by means of the SPC (Short PWM Code) protocol with enhanced features based on SENT (Single Edge Nibble Transmission, defined by SAE J2716), a value derived from the Hall-Cell and the temperature of the Hall-Cell to an ECU.
SENT is a recently developed serial protocol used for sensors in the automotive industry. SENT exhibits several advantages over older serial links. SENT enable to provide sensors having a high resolution, which are immune to Electro Magnetic Perturbations and which are cost effective. An example of a SENT sensor is the Melexis 90809 Sensor. This sensor measures relative Pressure as well as Temperature, both with a 12 bit resolution. It is a fully integrated IC that comprises MEMS, analog front end circuitry, 16 bit microcontroller, analog back end circuitry and voltage regulators.